Mexico's new president-elect has called on both supporters and opponents to come together to tackle some of the nation's most pressing problems.

In Mexico City Wednesday, Felipe Calderon said his top priorities after taking office in December will be fighting crime, improving the economy and reducing poverty.

His opponent in the presidential election, Andres Manuel Lopez Obrador, has rejected Tuesday's ruling by the Federal Election Tribunal that declared Mr. Calderon Mexico's next president. Under Mexican law, the tribunal's ruling cannot be appealed.

Lopez Obrador has vowed not to concede defeat and has promised to continue to lead street protests against what he alleges was massive fraud in the July second election.

The election and subsequent claims of fraud have divided Mexico and represent a challenge to the country's fledgling democracy, just six years after President Vicente Fox's dramatic victory ended decades of one-party rule.

Lopez Obrador's supporters have camped out in the capital's historic Zocalo square for weeks. The leftist leader says he intends to establish a parallel government. He is calling for a big turnout at a rally to endorse his plan on September 16, Mexico's Independence Day.

Mr. Calderon will take office December 1, when Mr. Fox steps down at the end of his six-year term.